A280358 Number of n X 3 0..2 arrays with no element equal to more than one of its horizontal and vertical neighbors and with new values introduced in order 0 sequentially upwards.

4, 50, 571, 6727, 78800, 924579, 10844773, 127214104, 1492251709, 17504551617, 205333329586, 2408618523801, 28253780677867, 331424891961162, 3887708335839063, 45603925604339175, 534947030615649624

Offset: 1

Author

R. H. Hardin, Jan 01 2017

Keywords

• nonn

Comments

Column 3 of A280362.

Examples

			Some solutions for n=4
..0..1..1. .0..0..1. .0..1..0. .0..1..2. .0..1..2. .0..0..1. .0..1..2
..2..0..2. .2..2..0. .1..2..1. .2..0..1. .2..0..2. .2..2..0. .1..2..1
..1..0..2. .0..1..1. .1..0..0. .2..1..2. .0..1..0. .0..0..2. .0..2..0
..0..2..0. .2..0..0. .0..1..2. .1..0..1. .1..2..1. .1..1..0. .0..1..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A280362.

Formula

Empirical: a(n) = 10*a(n-1) +26*a(n-2) -58*a(n-3) -99*a(n-4) -63*a(n-5) -25*a(n-6) +229*a(n-7) -3*a(n-8) -16*a(n-9) +12*a(n-10) +16*a(n-12).